1. Field
This disclosure relates to the field of measurement of air and wind parameters.
2. Background Art
Conventionally, relative air speed is measured between a moving object, such as any airborne vehicle, e.g., an aircraft or helicopter, and the free airstream through which the airborne vehicle is flying using a mechanical instrument that compares the kinetic pressure, exerted by the moving airstream onto a first area facing the airstream with respect to the static pressure exerted on a second area generally perpendicular to the first area. Typically, such a conventional system employs pitot tubes, pneumatic tubing, and pressure transducers, which are exposed to the external environment and subject to not only degraded performance caused by calibration changes, but also catastrophic failures as a result of accidental breakage. Furthermore, this conventional type of air speed measurement device physically protrudes into the airflow, with a resultant drag penalty.
Also, conventionally, changes in altitude were measured using mechanical instruments sensitive to changes in pressure of the earth's atmosphere from one elevation to another. Accordingly, it is conventional to provide an aircraft with one or more static pressure ports so that the external air pressure is exerted upon a pressure measuring diaphragm contained within the aircraft.
However, significant inaccuracies may result from disturbances by the airflow in the region of the pressure port caused by icing, by air currents and turbulence, and by air compression effects or from changes in the orientation of the port relative to the airflow caused by changes in the attitude (i.e., the orientation relative to the ground) of the aircraft.
Furthermore, conventional approaches do not provide reliable systems and methods for making air data measurements at a sample location at a sufficient distance from the aircraft or any physical attachments thereto such that the measurement will not be subject to systemic errors of a sort that cannot always be fully compensated for such as those caused by air compression effects and airflow disturbances.